IgA glomerulonephritis (Berger's disease): evidence of high serum levels of polymeric IgA.
Eleven out of 15 patients with IgA mesangial glomerulonephritis (Berger's disease) had an increased proportion of serum IgA in 9-21S fractions on 5-40% sucrose density-gradient ultracentrifugation; the heavier fractions decreased at acid pH. Serum IgA purified by starch electrophoresis was subjected to reduction-alkylation yielding fragments of lower molecular weight. J chain was detected on urea alkaline polyacrylamide electrophoresis and the high-molecular weight IgA bound the human secretory component. In six patients treated with phenytoin for 1 year there was a decrease in polymeric IgA and an increase in monomeric IgA adopting a pattern similar to that of the controls. Our results show the presence of a large amount of true IgA polymers, partially as immune complexes, in the serum of patients with Berger's disease. These data together with their normalization after phenytoin treatment may open a new pathogenic and therapeutic approach to this entity.
D000936:Antigen-Antibody Complex / Q000032:analysis; D001704:Biopolymers; D002499:Centrifugation, Density Gradient; D004591:Electrophoresis, Polyacrylamide Gel; D005921:Glomerulonephritis / Q000188:drug therapy / Q000276:immunology*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007070:Immunoglobulin A / Q000032:analysis*; D007144:Immunoglobulin J-Chains / Q000032:analysis; D008970:Molecular Weight; D010672:Phenytoin / Q000627:therapeutic use
D000936:Antigen-Antibody Complex; D001704:Biopolymers; D007070:Immunoglobulin A; D007144:Immunoglobulin J-Chains; D010672:Phenytoin